In the past, a bio-information monitoring system which includes a laser blood-stream measuring device for measuring a blood stream of specimen is disclosed in, for example, Patent Document 1. That is, this bio-information monitoring system includes a laser blood-stream measuring device for measuring a blood stream based on a scattered light caused by the fact that a laser light irradiated in an organization of body is scattered in the organization of body.
Specifically, this laser blood-stream measuring device includes a containing case which contains irradiating means for irradiating a laser light into a body, detecting means for detecting a scattered light caused by the fact that a laser light irradiated by the irradiating means is scattered in an organization of the body, and concentrating means for concentrating the scattered light and causing the detecting means to carry out detection. The outer surface of the containing case is structured in such a way that a contacting surface for contacting a surface of organization of body at the measuring time is formed into an approximate plane. Patent Document 1: Japanese Patent No. 3490433